The invention relates to an induction furnace having a furnace bottom comprising a crucible, an induction winding and a gas-tight casing, having also a lid for the furnace bottom which has at least one gas connection, a charging valve and a pouring arrangement, in which the furance bottom and the lid are releasably, but in gas-tight manner, connected together and are tippably supported about a tipping axis in a furnace stand when connected, by a pivot bearing and a tipping mechanism.
In such gas-tight induction furances, which can be used with a shielding gas or under vacuum, materials are usually melted and held ready for casting which would suffer oxidation and/or would absorb gas if melted in air. Principally, such furnaces are used for melting metals which are relatively reactive at their melting temperature.
Such induction furnaces need a whole series of ancillary equipment which as a rule is affixed to the lid or connectable to the lid such as charging equipment, slag-removal equipment, measuring and monitoring equipment, pouring equipment etc. Also, the necessary gas connections for supplying a shielding gas or evacuation by vacuum pumps are usually attached to the lid.
In the known induction furnaces of the kind described above the hinge bearing for the tilting movement is on the furance bottom and also the tilting mechanism works on the furnace bottom. For this, the furnace bottom has a carrying frame which is supported by bearing spigots in a furnace stand. This method of construction however leads to a number of problems.
The crucible inside induction furnaces which comprises in the usual way a ceramic material and is usually also known as "brickwork", is subject to more or less rigorous wear, from thermal and mechanical demands. To the mechanical demands belong the movement of the melt usually occasioned by inductive stirring of the bath, which is applied not only for alloy formation but also for intensifying gas exchange. It is therefore in many cases necessary, after the melting of several charges, to examine the furnace bottom including the induction winding and to replace the crucible or the brickwork as necessary.
In the known induction furnaces described above it was arranged that one lifted off the freely movable lid and carried out the necessary inspection and repair work on the furnace bottom. However, in doing this, the lid, which, on account of its numerous attachments and fittings was a relatively expensive item, could not be further used and then the user had to have at his disposal a second complete induction furnace of the known type. So long as the furnace bottom remained in the furnace stand for carrying out the inspection and repair operations, this also compelled the associated vacuum pumps to be stopped, so that the productivity of the whole induction melting plant was greatly reduced. Here it is to be noted that the furnace lid with all its attachments and fittings and the furnace stand with the supply equipment for the induction melting plant needed to be inspected or serviced at very much greater time intervals.
The invention is based therefore on the problem of providing an induction furnace of the type described above in which the inspection and repair work on the furnace bottom can be carried out much more easily and in which the furnace lid with its costly attachments and fittings can also be used further during the inspection and repair work.